Minitest basics (assert style) in Ruby - Mini Project: Build & Apply

Minitest basics (assert style)

📖 Scenario: You are learning how to write simple tests in Ruby using Minitest. Testing helps you check if your code works as expected, like checking if a calculator adds numbers correctly.

🎯 Goal: Build a small Ruby test file using Minitest with assert style to check if a method returns the correct sum of two numbers.

📋 What You'll Learn

Create a method called add that takes two numbers and returns their sum

Write a Minitest test class called TestAdd

Inside the test class, write a test method called test_addition

Use assert_equal to check if add(2, 3) returns 5

Run the test and print the result

💡 Why This Matters

🌍 Real World

Testing code helps catch mistakes early, just like checking your homework before submitting it.

💼 Career

Many software jobs require writing tests to ensure code quality and prevent bugs.

1

Create the add method

Write a method called add that takes two parameters a and b and returns their sum using a + b.

Ruby

# Your code here to define the add method

Need a hint?

Use def to define the method and return the sum with a + b.

2

Set up the Minitest test class

Add require "minitest/autorun" at the top. Then create a test class called TestAdd that inherits from Minitest::Test.

Ruby

def add(a, b)
  a + b
end

# Your code here to require minitest and create TestAdd class

Need a hint?

Use require "minitest/autorun" to load Minitest. Define the class with class TestAdd < Minitest::Test.

3

Write the test method with assert_equal

Inside the TestAdd class, write a method called test_addition. Use assert_equal 5, add(2, 3) to check if adding 2 and 3 returns 5.

Ruby

require "minitest/autorun"

def add(a, b)
  a + b
end

class TestAdd < Minitest::Test
  # Your code here to write test_addition method
end

Need a hint?

Define the test method with def test_addition and use assert_equal to compare expected and actual values.

4

Run the test and print the result

Run the Ruby file with Minitest. The test output should show 1 runs, 1 assertions, 0 failures, 0 errors. Add puts "Test completed" after the test class to print confirmation.

Ruby

require "minitest/autorun"

def add(a, b)
  a + b
end

class TestAdd < Minitest::Test
  def test_addition
    assert_equal 5, add(2, 3)
  end
end

# Your code here to print confirmation message

Need a hint?

Use puts "Test completed" to print a message after tests run.